[rnd me]

using the search param (?), instead of the hash (#) will cause all current browsers to refresh the page, not something i think you want.

so, in order to use a url, it would have to be a hash.

this means that you need to create a 'landing page'- a simple html/js page the immediately converts the hash to a search and transfers the url to your php script.

note that this would be incoming only; bookmarking a dynamic page would use the search, not the hash. make sure your server can find both versions.

edit:
one more idea: use ?s and a full-screen iframe to show your content. the hash of your top page can change while the search of the iframe changes